SYNC(2) | Linux Programmer's Manual | SYNC(2) |
NAME
sync, syncfs - commit buffer cache to diskSYNOPSIS
#include <unistd.h>Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_BSD_SOURCE || _XOPEN_SOURCE >= 500 || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
_GNU_SOURCE
DESCRIPTION
sync() causes all buffered modifications to file metadata and data to be written to the underlying file systems.RETURN VALUE
syncfs() returns 0 on success; on error, it returns -1 and sets errno to indicate the error.ERRORS
sync() is always successful.- EBADF
- fd is not a valid file descriptor.
VERSIONS
syncfs() first appeared in Linux 2.6.39; library support was added to glibc in version 2.14.CONFORMING TO
sync(): SVr4, 4.3BSD, POSIX.1-2001.NOTES
Since glibc 2.2.2 the Linux prototype for sync() is as listed above, following the various standards. In libc4, libc5, and glibc up to 2.2.1 it was "int sync(void)", and sync() always returned 0.BUGS
According to the standard specification (e.g., POSIX.1-2001), sync() schedules the writes, but may return before the actual writing is done. However, since version 1.3.20 Linux does actually wait. (This still does not guarantee data integrity: modern disks have large caches.)SEE ALSO
bdflush(2), fdatasync(2), fsync(2), sync(8), update(8)COLOPHON
This page is part of release 3.53 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.2012-05-04 | Linux |